1. Field of the Invention
The subject matter disclosed generally relates to the field of hard disk drives.
2. Background Information
Hard disk drives contain a plurality of magnetic heads that are coupled to rotating disks. The heads write and read information by magnetizing and sensing the magnetic fields of the disk surfaces. There have been developed magnetic heads that have a write element for magnetizing the disks and a separate read element for sensing the magnetic fields of the disks. The read element is typically constructed from a magneto-resistive material. The magneto-resistive material has a resistance that varies with the magnetic fields of the disk. Heads with magneto-resistive read elements are commonly referred to as magneto-resistive (MR) heads.
Each head is attached to a flexure arm to create an subassembly commonly referred to as a head gimbal assembly (xe2x80x9cHGAxe2x80x9d). The HGA""s are attached to an actuator arm that has a voice coil coupled to a magnet assembly. The voice coil and magnet assembly create a voice coil motor that can pivot the actuator arm and move the heads across the disks.
Information is typically stored within annular tracks that extend across each surface of a disk. The voice coil motor can move the heads to different track locations to access data stored onto the disk surfaces. Each track is typically divided into a plurality of adjacent sectors. Each sector may have one or more data fields. Each data field has a series of magnetic transitions that are decoded into binary data. The spacing between transitions define the bit density of the disk drive. It is generally desirable to provide a high bit density to increase the overall storage capacity of the drive.
FIG. 1 schematically shows the layers of a double layered perpendicular magnetic recording (xe2x80x9cPMRxe2x80x9d) media 1. The media is used as a disk for a hard disk drive. The double layer PMR media 1 includes a first magnetic layer 2 located over a substrate 3. The first magnetic layer 2 and substrate 3 are typically separated by an underlayer 4 that strengthens the adhesion of the first material.
The first magnetic layer 2 is covered with an intermediate layer 5 and a second layer of magnetic material 6. The second magnetic layer 6 is protected with an overcoat layer 7, typically a diamond-like-carbon (DLC). The overcoat layer 7 may be covered with a layer of lubricant 8 to minimize any frictional contact between the head and the disk.
The first magnetic layer 2, sometimes referred to as the soft underlayer is typically constructed from NiFe, CoZrNb, CoTaZr, etc. These material typically exhibit low saturation magnetization. Additionally, with compositions of the prior art it is difficult to obtain favorable negative nucleation fields in the disk.
A disk for a hard disk drive. The disk includes a first layer of magnetic material separated from a second layer of magnetic material by an intermediate layer. The first layer of magnetic material includes iron, hafnium and nitrogen (FeHfN).